1. Field of the Invention
The present invention is related to a pickup for accessing moving storage media according to the preamble of claim 1. Pickups are used as part of a recording and/or reproducing apparatus, e.g. of a DVD player, a DVD recorder or of similar apparatuses.
2. Description of the Prior Art
A pickup for accessing moving storage media records and/or reproduces information with respect to the moving storage media carrying substantially parallel information tracks, namely a turning disk, while moving in the radial direction of the disk.
A pickup, referred to as an objective lens actuator, which uses an actuator with a flat form, referred to as an objective lens holder, facilitates manufacturing and fabrication, is described in the US 2006/0143639. The pickup controls the focus direction, tracking direction and radial tilt direction of its optical pickup head.
The pickup comprises a carrier, constituted as a ferromagnetic yoke, a damper holder and a printed circuit, the actuator with a lens and suspension wires extending from a rear of the carrier and joining the carrier and the actuator. The actuator is constituted as a substantially rectangular flat board. The flat board is arranged orthogonal to the focus direction and carries tracking coils and focus coils. The lens is arranged on the upper side, which is directed to the disk, at the center of the flat board. A counter weight can be provided.
In addition the pickup comprises a magnet configuration connected to the carrier with four tracking magnets and two focus magnets. Two tracking magnets each are arranged at opposite sides of the flat board in the tracking direction and extend orthogonal to the focus direction above and under the flat board. The two focus magnets are arranged in front of and behind the flat board and extend orthogonal to the direction of the tracks.
The suspension wires both movably support the actuator, as well as apply currents to the coils on the actuator. The coils and the magnet configuration, all together referred to as a magnetic driving portion, initiate the movements of the actuator. The actuator is movable relatively to the carrier in the focus direction, the tracking direction and in the radial tilt direction in a plane spanned by the focus direction and by the tracking direction, respectively. By moving the actuator with the lens, the beam spot can be accurately located on the disk.
As a disadvantage can be seen, that there is a certain distance between the lens arranged at the center and the outer surfaces of the pickup. Since some driving elements are needed in the center opening of a running disk, the lens of the pickup cannot be positioned near the center of the disk. As a result, the recording and/or reproducing of data is not possible in a certain region around the center of the disk.
An additional thin pickup, referred to as an objective lens driving device, is described in the JP 101721157 A2. The device comprises tracking driving magnets and focusing driving magnets arranged around a lens holder for holding an objective lens. Projecting poles protrude toward these magnets from the lens holder and tracking driving coils and focusing driving coils are wound on these projecting poles.
This round pickup is suspended in its center. As a disadvantage, the movements of the lens in the tracking direction follow a circular arc, which is more strongly curved than that of a pickup with suspension wires. The pickup provides a lens, which is arranged in the direction of the tracks in front of the lens holder and in the tracking direction in the middle of the pickup. The pickup is also not able to record and/or reproduce data in a certain region around the center of the disk.